Dear Ms. Dew,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located the series Carded Records Showing Military Service of Soldiers Who Fought in Volunteer Organizations During the Spanish-American War in the Records of the Adjutant General's Office, 1762 - 1917 (Record Group 94). This series is indexed by Indexes to the Carded Records of Soldiers Who Served in Volunteer Organizations During the Spanish-American War in Record Group 94. Some of the service records and the index cards in these series have been made digitized and made available online through the Catalog. We were unable to locate a digitized copy of the records for Frederick L Clark. You may wish to sample some of the other compiled military service records that are available in order to get an idea of the types of information that may be found in these types of service records. In addition, there may be a pension application for him which is also not available online.
To order records that have not already been digitized, please fill out a NATF Form 86 for the service records and a NATF Form 85 for the pension records and mail the completed forms to the address listed on the form. You also may place your order online using eservices.archives.gov. For more information see Requesting Copies of Older (pre-WWI) Military Service Records.
Please note that the National Archives and Records Administration (NARA) has suspended reproduction and digitization services until further notice due to COVID-19. Orders will not be serviced until operations can resume safely. Once operations resume, document reproduction requests will be filled in the order in which they were received. We apologize for this inconvenience and appreciate your understanding and patience.
Finally, we located Correspondence of the 46th U.S. Volunteer Infantry Regiment, 5/1900 - 9/1900 in Record Group 94. For more information, please contact National Archives at Washington, DC - Textual Reference (RDT1) at Archives1reference@nara.gov.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgement as well as a substantive response to your reference request from RDT1.
We hope this is helpful. Best of luck with your family research!